The world’s second-largest sea star is literally melting away. Plagued by a deadly pathogen, the sunflower sea star has disappeared dramatically in parts of its habitat along the Pacific Coast of North America.
The animals are suffering from Sea Star Wasting Syndrome, which causes them to develop lesions, become lethargic, lose their arms and “within days disintegrate into gooey masses,” per the National Oceanic and Atmospheric Administration (NOAA).
Last week, NOAA officials submitted a proposal to list the sunflower sea star as threatened under the Endangered Species Act. After 90 percent of the animal’s population was wiped out between 2013 and 2017, this recommendation means the sea stars are considered likely to be at risk of extinction soon.
“Sea star wasting disease came through quite a few years ago, and that pretty much decimated the population,” Ben Morrow, an aquarist at the Omaha Zoo, tells WOWT’s Bella Caracta. “Certain other species of stars have been able to recoup their numbers, but the sunflower star’s not ever really come back.”
Beyond the threat to the species itself, its decline is driving a collapse of California’s kelp forest ecosystem. With fewer sunflower sea stars in the ocean, their sea urchin prey has been left to grow and consume kelp uncontrollably, forming vast “urchin barrens” where kelp forests used to be. On top of that, an unusual ocean heat wave in 2014 and an El Niño event also exacerbated the kelp forest problem.
“It’s a naturally dynamic system that has been really resilient to extreme events in the past, but the die-off of sunflower stars caused the resilience of the ecosystem to plummet,” Meredith McPherson, who was then a researcher at the University of California, Santa Cruz, said in a statement in 2021. “As a result, the kelp forests were not able to withstand the effects of the marine heatwave and El Niño event combined with an insurgence of sea urchins.”
Healthy kelp forests provide important habitats for a variety of species, including fish, invertebrates, marine mammals and birds. They also help sequester large amounts of carbon. Per acre, coastal ecosystems can capture 20 times more carbon than land forests do. In total, seaweed, including kelp, is thought to store nearly 200 million tons of carbon dioxide each year—equal to about a year’s worth of emissions from New York state, wrote Isabelle Gerretsen for BBC Future Planet in 2021. In California, kelp restoration and an urchin removal project have helped bring back some of the ecosystem.
Young sunflower sea stars can gobble up as many as five to seven juvenile urchins per day, University of Washington research scientist Jason Hodin told Salish Sea Currents magazine’s Maddison Hicks last year. As adults, the sea stars have up to 24 arms and grow to more than three feet from arm to arm, per the Monterey Bay Aquarium. They range in color from orange to red to purple or beige. The International Union for Conservation of Nature has listed the species as critically endangered with a decreasing population trend.
Following a 2021 petition from the Center for Biological Diversity, NOAA Fisheries reviewed the sunflower sea star’s conservation status before ultimately recommending to list it as threatened. A final decision will be made next year, and if it goes through, this would be the first sea star to receive protection under the Endangered Species Act, writes the New York Times’ Catrin Einhorn.
This listing would not only raise awareness of the species’ decline, but it could help boost funding for studying the deadly wasting disease, per KATU.
“I’m ecstatic that the sunflower sea star will get the safeguards of the Endangered Species Act,” Miyoko Sakashita, the Center for Biological Diversity’s oceans program director, tells the Times. “A climate-fueled pandemic nearly wiped them out, and I’m optimistic that a threatened listing will assist their recovery.”